Java array declaration

Array variables must first be declared before an array can be used in a program. The following is the syntax of an array variable:

dataType[] arrayRefVar;  //首选的方法
dataType arrayRefVar[];  //效果相同但不是首选方法

Java language uses new operator to create arrays

dataType[] arrayRefVar = new dataType[arraySize];
//定义
int[] nums;
//创建
nums = new int[10];
//变量类型 变量名字 = 变量值
int[] nums = new int[10];

Elements of an array are accessed by index, which starts at 0

获取数组长度
array.length

public class ArrayDemo01 {
    //变量类型  变量名字 = 变量值
    //数组类型

    public static void main(String[] args) {
        //int[] nums;//1.定义

        //nums = new int[10];//2.创建一个数组
        int[] nums = new int[10];
        //3.给数组元素中赋值
        nums[0] = 1;
        nums[1] = 2;
        nums[2] = 3;
        nums[3] = 4;
        nums[4] = 5;
        nums[5] = 6;
        nums[6] = 7;
        nums[7] = 8;
        nums[8] = 9;
        nums[9] = 10;

        //计算所有元素的和
        int sum = 0;

        //获取数组长度：arrays.length
        for (int i = 0; i < nums.length; i++) {
            sum = sum + nums[1];
        }

        System.out.println("总和位："+sum);

    }
}